1. Field of the Invention
The present invention is related to biomarkers for liver diseases and method for using the same, in which a method for screening autoantigens is employed to identify biomarkers that can be used in detecting liver diseases. The identified biomarkers are further developed into detection kits to detect the presence of autoantibodies or autoantigens in specimens for screening of liver diseases.
2. Description of Related Art
People with impaired immune functions are prone to develop immune diseases. The etiology of many human diseases may be traced to our immune system in any of the three conditions described below. The first is reduced immunity, lower activity of immune cells, or reduced quantity of immune cells, such that the human body cannot fight off the invading bacteria, virus or mold, and becomes susceptible to contagious diseases, such as common cold, flu, pneumonia, enteritis, or even hepatitis and AIDS. The second condition is immunodeficiency or over-reaction of the immune system where the invading substances are not germs, but tiny pollens or macromolecular proteins in the food ingested, against which the immune system releases a large amount of antibodies. Such attack and defense occur in our cells, causing a chain of reactions which is also called allergy. When real pathogens such as bacteria, virus or mold attack the human body at this time, the immune system is no longer able to put up resistance. The third condition of impaired immune system is the immune cells attack normal cells in the human body, called autoimmune disorder as in the case of rheumatoid arthritis, lupus erythematous, and herpes. Such immune diseases arise from our own immune system having an identification problem that autoantibodies are produced against human body's own cells, resulting in tissue damage and illnesses.
It is now known that autoantibodies are present not just in autoimmune diseases. More and more studies indicate that in the immune response to cancer, autoantigen (from the tumor) and autoantibody (from the body) exist in some cases. Thus the detection of tumor autoantigen that elicits body response may be directed towards and applied in the testing, diagnosis, or prognosis of cancer, and furthermore, in the treatment of disease.
U.S. Pat. No. 6,631,330, 5,137,807, 5,830,667, 6,264,949, and 5,985,542 disclose the use of biomarkers in the diagnosis of cirrhosis, fibrosis or autoimmune hepatitis (All-I); U.S. Pat. Nos. 4,994,374 and 5,175,084 disclose the use of biomarkers in the diagnosis of hepatocellular carcinoma; U.S. Pat. No. 6,410,724 uses DNA primer associated with hepatocellular carcinoma as a diagnostic tool. But the biomarkers disclosed in those patents lack accuracy or are susceptible to interference to a certain extent.
U.S. Pat. No. 5,891,436 and Publication No. 20030138860 disclose the use of biomarkers to detect the presence of autoantibodies in human serum as a diagnostic tool for primary biliary cirrhosis or hepatocellular carcinoma. Those patents confirm the existence of autoantibodies in cancer patients and thereby establish the rational for using biomarkers in cancer screening.
Cancer has been the leading cause of death in Taiwan since 1982, whereas liver cancer is ranked among the top as the cause of death in both men or women. Thus it is important to find biomarkers with high accuracy and not susceptible to interference and use those biomarkers to develop detection kits for liver cirrhosis and cancer to effectively screen patients with liver diseases in the hope that early diagnosis and early treatment can help lower the mortality rate.